# Binary search program in c using divide and conquer method

The following code offers an interface compatible with the requirement of this task, and returns either the index of the element if it has been found or f otherwise. As the player, an optimal strategy for the general case is to start by choosing the range's midpoint as the guess, and then asking whether the guess was higher, lower, or equal to the secret number. This process repeats until one has reached the secret number.

An assembler version of this routine attended to all these details. This postcondition cannot be proved without a precondition that Source is ordered. Unfortunately, there is no three-way comparison test for character data. Could be for example a csv table where the first column is used as key field.

The algorithms return the index of some element that equals the given value if there are multiple such elements, it returns some arbitrary one. Could be for example a csv table where the first column is used as key field. They differ by how they treat multiple values equal to the given value, and whether they indicate whether the element was found or not. It is the classic example of a "divide and conquer" algorithm. This has the array indexed from 1 to N, and the "not found" return code is zero or negative.

The algorithms are as follows from Wikipedia. The following code offers an interface compatible with the requirement of this task, and returns either the index of the element if it has been found or 'Not Found' otherwise:. If unsigned integers are used, an overflow will result in losing the largest bit, which will produce the wrong result.

Instead of using an intrinsic function, a general binary search algorithm is implemented using the language alone. Analysis, Classification, and Examples. The calculation of "mid" cannot overflow, since Maple uses arbitrary precision integer arithmetic, and the largest list or array is far, far smaller than the effective range of integers. It is the classic example of a "divide and conquer" algorithm. Further, the compiler may itself choose to re-order the various code pieces.

As an analogy, consider the children's game " guess a number. There are several binary search algorithms commonly seen. This postcondition cannot be proved without a precondition that Source is ordered. If it was, print the index also.

Analysis, Classification, and Examples. These branch tests may in turn be made in an order that notes which option if any involves "falling through" to the next statement, thus it may be better to swap the order of labels 3 and 4. Could be for example a csv table where the first column is used as key field. Returns a positive index if found, otherwise the negative index where it would go if inserted now.